Ofa And Reading Them

[BIGWRIGHT]

Can anyone tell me how to read OFA's and PENN HIP I always find this confusing what the percentages should be and all that. Like what the parents should be for great OFA for pups.

[Judi W]

With OFA, more important than the ratings (as long as they are passing) is the strength within the family. This means the siblings of the parents and the grandparents should have a high percentage of HD free. You are actually breeding families, not just individuals. I believe that criteria should apply to Penn Hip also, but their evaluations confuse me as the evaluation seems to be dependent upon the percentage of their database which I do not fully understand. Sorry, I can't help with that part of your question.

[MARYDVM]

PennHip is used a lot by American Bulldog breeders. The measurment that is recorded is the DI or distraction index. The higher the DI, the looser the hip joint is(the more"distraction" you get when pressure is applied on the inner thigh). Tighter hips are better hips, so a low DI is what you are aiming for. Some breeds have an average of tighter hips (low DIs), but those with a lot of hip dysplasia have a high average. I think the AB average DI was 57 last time I checked. That means that half of the tested ABs had better hips, and half had worse.... 57 is a pretty loose hip score, so it gives you an idea of how poor the hip scores are in this breed. Breeders should try to breed only dogs who have tighter than average hips. Over time this will result in lowering the average DI for the breed as tighter hipped offspring are produced. The PennHip report will also say if degenerative joint disease (DJD) is present, and no dog should be bred, no matter what the DI score is if DJD is present. The PennHip evaluation is most valuable in breeds with a high level of hip dysplasia where you can compare your dog's hip status to the rest of the breed and make breeding decisions that will hopefully improve the health of future generations. I think the best DI recorded for an AB was .28 .28. A good score in this breed would be .30 to .40s. I don't know what the average DI for Rotties is.

[Judi W]

Thanks for the better explanation Mary. That is pretty much what my impression was. To be honest, with the very wide Rottweiler gene pool of HD free dogs, I don't think percentages is what we need to use for selection criteria. I can see where with a limited gene pool and a high incidence, small improvements would count for a lot hence the percentage idea.

[Rottzilla]

Mary - Someone made a comment to me this weekend and I thought I'd share it here. We were talking about a specific group of dogs that are largely "Fair & Good" by OFA scoring... yet the entire group have this beautiful gait with great reach and drive... seeming to nearly float over the ground. One person wondered if the slight laxity present in the hip, based on the OFA "Fair to Good" rating, allowed them the greater movement.

What are your thoughts on this?

[MARYDVM]

The Fair reading can also come about because of the way the hip socket is shaped - not due to real laxity at all. The only way to tell how loose those hips really are is to do the PennHip. There are a number of ABs with Fair (or worse) ratings that have tighter than average hips. The PennHip is also the only system that can tell you if your dog's hips are good as early as 4 months of age.

I've heard the "looser = smoother movement" theory, but I don't buy it. If the ball of the hip fits tightly into a well rounded socket the movement is smooth and easy. If there is laxity in the joint the ball of the femur can bounce in and out slightly with each stride, or wobble from side to side - not a smooth way of moving.

The difference between a "Good" and an "Excellent" rating is insignificant to me. They are both very functional hips.

[marianne]

In the past my Rottweilers all had the OFA's before breeding anything less than good was not used for breeding. The pedigree's of grandparents and back also had the OFA ratings. This is very important,but not always 100% accurate.Even though we check the dogs for H-D it still can appear.
With my bulldogs...most x-rays will show H-D to some vets. They do have very lose sockets and are to have a rolling gait.
The Penn-Hip is a very good tool to use. the dog can be tested at a early age. The only drawback is to find a vet that has the knowledge and equipment to do the Penn-Hip testing. I have yet to find that vet in my area.